Recent scientific investigations have shown that many chemicals used in plastics, pharmaceuticals, pesticides, cosmetics, food additives, etc., are endocrine disruptors (EDs). EDs interfere in various ways with hormones such as estrogens to have significant adverse effects on many behavioral and physiological processes. ED effects (e.g. estrogenic or anti-estrogenic) sometimes occur at very low (picomolar to nanomolar) concentrations, especially on fetal or developing mammals (including humans). The prevalence and actions of EDs in our environment warrant the development of valid assay methods. Consequently, various governmental bodies (e.g., EPA, FDA, and ICCVAM) and proactive corporations have explicitly expressed a desire to have in vitro robotic assays for EDs, such as anti-estrogenic activity (anti-EA). However, no robotic anti-EA assay is commercially available. To begin to meet these governmental, scientific and commercial needs, CertiChem (CCi) has completed a Phase I SBIR grant showing that it is feasible to develop an anti- EA robotic assay that would be valid (i.e., reliable, accurate, versatile, rapid, and cost effective) using MCF-7 cells. In this Phase II application, CCi now proposes to develop this robotic assay for anti-EA for commercialization by repeatedly assaying a set of 78 reference test chemicals to confirm the reliability and accuracy of CCi's proposed anti- EA assay. CCi also proposes to demonstrate the versatility of this assay by examining the anti-EA in a set of antioxidants used in foodstuffs and plastics. Finally, CCi proposes to perform HPLC separation assays on some reference test chemicals to confirm that their anti-EA is not due to contamination and to enhance the versatility of this assay for commercial use. Development of a robotic screening assay for anti-EA is commercially, scientifically, and socially important because of the large number of chemicals (>10,000) - much less chemical mixtures - that should now be screened for anti-EA by profit, non-profit, or governmental entities. Development of a robotic assay for anti-EA is desired as part of the mission of NIEHS, EPA and ICCVAM. Recent scientific investigations have shown that many (perhaps over 10,000) chemicals used in common products such as plastics, pesticides, cosmetics, and food additives have estrogenic/anti-estrogenic activities that severely interfere with normal estrogen actions to produce adverse effects on many behavioral, reproductive, and physiological processes in humans. In this Phase II proposal, CertiChem (CCi) proposes to develop a very sensitive and accurate assay to measure anti-estrogenic activity in a set of reference test chemicals and in common consumer products. CCi proposes to use these data and CCi's data on estrogenic activity on many chemicals to identify which chemicals have anti-estrogenic activity and to work with various firms to design consumer products that are free of chemicals that release anti-estrogenic or estrogenic activities. [unreadable] [unreadable] [unreadable]